Multiple-pole two-position dual-wafer ultra-high-frequency transmit-receive switch control



3,146,397 REQUENCY 8 25, 1964 s. L. BROADHEAD, JR

MULTIPLE-PQLE TWO-POSITION DUAL-WAFER ULTRA-HIGH-F TRANSMIT-RECEIVE SWITCH CONTROL Filed May 23. 1960 To A TfN/VA Oscauvrwe FIG I C J 30 jFlE 4 FIE E F"; 3

INVENTOR. SAMUEL A. BROAD/{40 JR United States Patent 3,146,397 MULTIPLE-POLE TWO-POSITION DUAL-WAFER ULTRA HIGH FREQUENCY TRANSMIT RE- CEIVE SWITCH CONTROL Samuel L. Broadhead, J12, Cedar Rapids, Iowa, assignor to Collins Radio Company, Cedar Rapids, Iowa, a corporation of Iowa Filed May 23, 1960, Ser. No. 31,066 3 Claims. (Cl. 325-21) This invention relates in general to switches and in particular to a transmit and receive switch wherein the unused contacts are grounded when in the inoperative position.

The switch of this invention is designed so that when radio frequency energy, as for example in the vicinity of 400 megacycles, is switched, the disconnected circuitry is grounded so as to prevent radio frequency pickup. This switch is also designed so that a single mixer may be used for both transmission and reception in a radio system.

Another object of this invention is to provide a radio frequency transmit-receive switch which has a continuous surge impedance throughout the switch and obtains a very low standing wave ratio in the frequency range of the design.

Another feature of the switch is that very high attenuation is obtained between the input and output of the radio frequency, which prevents oscillations.

Further features, objects and advantages of the invention will become apparent from the following description and claims when read in view of the accompanying drawings, in which:

FIGURE 1 is a schematic illustration of the switch according to this invention;

FIGURE 2 illustrates one side of the switch with the top cover removed;

FIGURE 3 shows the side of the switch; and

FIGURE 4 illustrates the second side of the switch with the cover removed.

FIGURE 1 illustrates the first side of a switch 11. Terminals 10, 12, 13, 14, 15, 16, and 17 are mounted about the periphery of the switch 11. Contacts 12, 14, 15, and 17 are connected to a common ground plane, as for example the frame of the switch. Contact might be connected to an antenna, not shown. Contact 13 is connected to a lead 18. Contact 16 is connected to a lead 19.

A first shorting bar 21 is rotatably supported at the center of the switch and extends from contacts 17 and in one position, and when rotated to a second position by control shaft 22 extends from contact 16 to contact 10. A second shorting bar 23 extends fromthe contact 10 to contact 13 in the first position and from contact 12 to contact 14 in the second position. Shaft 22 is also connected to the shorting bar 23 and rotates it with bar 21.

The opposite side 25 of the switch 11 has a wafer 24 which has contacts 26, 27, 28, 29, 30, 31, and 32 spaced about its periphery. Contacts 27, 28, 30, and 32 are connected to ground, which might be the case of the switch. Contact 26 is connected to lead 19 which extends to contact 16 of the other side of the switch. Contact 29 is connected to lead 18 which is connected to connected to contact 13 on the other side of the switch. contact 31 is connected to lead 32a which leads to a mixer 33. Mixer 33 receives an input from an oscillator 34. The mixer 33 is a bilateral and is connected to a terminal 35.

A radio frequency amplifier 36 is connected between 0 leads 18 and 19 and has an input at lead 18 and an output 7 at lead 19.

A third shorting bar 38 is rotatably supported by the wafer 24 and in a first position extends from contact 31 to contact 26 and in a second position extends from contact 27 to contact 32. A fourth shorting bar 37 in a first position extends from the contact 28 to contact 30 and in the second position from the contact 29 to the contact 31. Shaft 22 is connected to shorting bars 37 and 38 and a knob 39 is connected to shaft 22 to rotate it and the four shorting bars from the first to the second positions.

In operation the knob 39 is moved to the receive position, which places the shorting bar 23 in engagement with contacts 19 and 13 and shorting bar 38 in engagement with contacts 26 and 31 such as shown in FIGURE 1. The shorting bar 21 would engage grounded contacts 15 and 17 and the shorting bar 37 would engage the grounded contacts 28 and 30. An incoming signal from the antenna, not shown, would pass from contact 10 through shorting bar 23 to contact 13 to lead 18. Since contact 29 is unengaged, a signal cannot pass to shorting bar 38; therefore, it will pass through the radio frequency amplifier 36 from point B to point A and to contact 26 through the shorting bar 38 to contact 31 and consequently to the mixer 33 through the lead 32a and will provide an input to a conventional receiver LF. that may be connected to terminal 35.

It is to be noted that during reception the shorting bars 37 and 21 are grounded at both ends to eliminate radio frequency pickup. In transmission the knob 39 would be rotated to the transmit position and the shorting bar 21 would be moved to engage contacts 16 and 10 and the shorting bar 37 would be moved to engage contacts 29 and 31. The shorting bar 38 would engage contacts 27 and 32 and shorting bar 23 would engage contacts 12 and 14. An output signal to be transmitted would be supplied to the mixer 33, mixed with an output of the injection oscillator 34 and passed to contact 31. The shorting bar 37 would connect it to the contact 29 and it would pass through the lead 18 to the RF. amplifier 36. From point A it would pass from lead 19 to contact 16 through the shorting bar 21 to the antenna through contact 10.

It is seen in transmission and reception that the unused shorting bars are grounded at both ends to eliminate radio frequency pickup.

FIGURE 2 illustrates a first side of the actual switch of this invention and comprises a body portion 41 which is formed with a central opening 42. A first disc 43 is rotatably mounted on one side of the switch. Contacts 10 and 1217 are mounted about the periphery of the switch. The shorting bars '21 and 23 are rotatably supported by disc 9 and shaft 22 and are insulated therefrom by the plastic disc 43. Terminal A corresponds to point A in FIGURE 1. Contact D is connected to the antenna. Terminal B corresponds to point B in FIG- URE 1.

FIGURE 3 illustrates the side of the switch. Cover plates 50 and 51 are connected to the switch to enclose it.

FIGURE 4 illustrates the opposite side of the switch and shows shorting bars 37 and 38. The shaft 22 is connected to shorting bars 37 and 38 through insulating disc 44. Contacts 26, 27, 28, 29, 30, 31, and 32 surround the switch. Terminal C corresponds to point C in FIGURE 1.

It is seen that this invention provides an improved radio frequency switch wherein the unused terminals are grounded. A constant surge impedance is obtained. Very large attenuation between the input and outputs exists due to the actual shorting of the unused shorting bars. Another advantage is that the switch eliminates one mixer when used as a transmit-and-receive unit.

- Although it has been described with respect to preferred embodiments, it is not to be so limited, as changes and modifications may be made which are within the full intended scope of the invention as defined by the appended claims.

I claim:

' 1. In a control system for alternately switching a first lead and a second lead oppositely to the output and input terminals of an RF amplifier; dual switching wafers each having at least two switch positions; switch positioning means for simultaneously switching said dual switching water between switch positions; each of said dual switch wafer being provided with a pair of shorting bars connected for movement with said switch positioning means; each of said dual wafers having a plurality of fixed contacts; one of the fixed contacts of one of the dual switching wafers being connected to said first lead, and one of the :fixed contacts of the other dual wafer being connected to said second lead; a second fixed contact of each of said switching wafers being connected in common to one of the terminals of said R.F. amplifier; a third fixed contact of each of said switching Wafers being connected in common to the other terminal of said R.F. amplifier; a plurality of additional fixed contacts of each of said dual switching wafers being connected to ground; with said fixed contacts being positioned for a first one of the shorting bars of each respective switching wafer to provide a connection between the contact connected to the lead associated with that wafer and a contact connected to a terminal of said amplifier, and with the other shorting bar of each pair of shorting bars being in contact with grounded contacts at each end; and alternately When the switching means switches the dual switching wafers to the other switch position the other shorting bar of each pair of shorting bars being connected between the lead contact associated with that water and the contact connected to the opposite terminal of said amplifier, and the first one of the shorting bars of each of the pair of shorting bars being, for this other switch position, in contact with grounded contacts at each end.

2. The control system for alternately switching a first lead and a second lead oppositely to the output and input terminals of an RF. amplifier of claim 1, wherein said first lead is a radio frequency antenna lead, and said second lead is a radio frequency signal lead; with connection of said antenna lead to the output terminal of said R.F. amplifier in a transmit switch position mode of operation with the RF. signal lead connected to the input terminal; and in the alternate switch position, the antenna lead being connected to the RF. amplifier input terminal; and the RPE. output terminal being connected to the RF. signal lead for the radio frequency receive mode of operation.

3. The control system for alternately switching a first lead and a second lead oppositely to the output and input terminals of an RF. amplifier of claim 2, wherein said. RF. signal lead is connected to a mixer fed an injection frequency from a frequency source to provide an LP. output when the control system is switched to the receive mode of operation; and alternately, for said mixer to provide an RF. input to the RF. amplifier resulting from an IT. input and the injection frequency applied to said mixer from said frequency source for the transmit mode of operation.

References Cited in the file of this patent UNITED STATES PATENTS 2,222,085 Mohler Nov. 19, 1940 2,369,193 Vrooman Feb. 13, 1945 2,594,190 Mastney Apr. 22, 1952 2,598,534 Gordon May 27, 1952 2,769,127 Duncan et al Aug. 21, 1956 2,794,081 Luhn May 28, 1957 2,833,862 Tolson May 6, 1958 3,086,091 Reid Apr. 16, 1963 FOREIGN PATENTS 758,518 Germany Feb. 8, 1954 UNITED STATES PATENT UFFICE CERTIFICATE OF CORRECTIN v Patent No. 3,146,397 August 25, 1964 Samuel L. Broadhead, Jr

, It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent shouldread as corrected below.

Column 1, line 49, for "and", second occurrence, read to line 63, after "is", second occurrence, strike out "connected to"; line 65, for "contact" read Contact column 2, line 68, for "input" read inputs column 3, line 12 and 13, for "wafer", each occurrence, read wafers column 4, line 34, for "2,769,127" read 2,760,127

Signed and sealed this 29th day of December 1964.,

(SEAL) Attestu ERNEST w. SWIDER EDWARD J. BRENNER Attesting Officer 1 I (1ommi ssioner of Patents UNITED STATES PATENT orrlcE CERTIFICATE OF CORRECTION Patent No. 3., 146,397 August 25, 1964 Samuel L; Broadhead, Jr

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 1, line 49, for "and", second occurrence, read to line 63, after "is", second occurrence, strike out "connected to"; line 65, for "contact" read Contact column 2, line 68, for "input" read inputs column 3, lines 12 and 13, for "wafer", each occurrence, read wafers column 4, line 34, for "2,769,127" read 2,760,127

Signed and sealed this 29th day of December 1964,

(SEAL) Attest:

ERNEST W. SWIDER EDWARD J.. BRENNER Aitcsting Officer 'Commissioner of Patents 

1. IN A CONTROL SYSTEM FOR ALTERNATELY SWITCHING A FIRST LEAD AND A SECOND LEAD OPPOSITELY TO THE OUTPUT AND INPUT TERMINALS OF AN RF AMPLIFIER; DUAL SWITCHING WAFERS EACH HAVING AT LEAST TWO SWITCH POSITIONS; SWITCH POSITIONING MEANS FOR SIMULTANEOUSLY SWITCHING SAID DUAL SWITCHING WAFER BETWEEN SWITCH POSITIONS; EACH OF SAID DUAL SWITCH WAFER BEING PROVIDED WITH A PAIR OF SHORTING BARS CONNECTED FOR MOVEMENT WITH SAID SWITCH POSITIONING MEANS; EACH OF SAID DUAL WAFERS HAVING A PLURALITY OF FIXED CONTACTS; ONE OF THE FIXED CONTACTS OF ONE OF THE DUAL SWITCHING WAFERS BEING CONNECTED TO SAID FIRST LEAD, AND ONE OF THE FIXED CONTACTS OF THE OTHER DUAL WAFER BEING CONNECTED TO SAID SECOND LEAD; A SECOND FIXED CONTACT OF EACH OF SAID SWITCHING WAFERS BEING CONNECTED IN COMMON TO ONE OF THE TERMINALS OF SAID R.F. AMPLIFIER; A THIRD FIXED CONTACT OF EACH OF SAID SWITCHING WAFERS BEING CONNECTED IN COMMON TO THE OTHER TERMINAL OF SAID R.F. AMPLIFIER; A PLURALITY OF ADDITIONAL FIXED CONTACT 